1. Field
The present disclosure relates generally to airflow and, in particular, to measuring the velocity of the airflow. Still more particularly, the present disclosure relates to a method and apparatus for mapping the multiple velocities of airflow that may be found in a duct.
2. Background
A duct is an enclosed passage or channel for conveying a substance, such as a gas or liquid. Ducts are commonly used throughout an aircraft. For example, ducts are part of a duct system used in an air distribution system for an environmental control system in the aircraft.
An air distribution system in an aircraft may be used during the operation of components in an environmental control system. For example, the ducts in the air distribution system may be used to supply or remove air from different locations in the aircraft. The movement of air into or out of these locations may occur during the operation of systems, such as a cabin air conditioning and temperature control system (CACTCS), a cabin pressure control system (CPCS), an electrical and electronic cooling system (EECS), an integrated cooling system (ICS) for a cargo bay, a power electronics cooling system (PECS), and other suitable systems.
Each of these systems employs airflow management. For example, one or more of these systems may perform flow balancing, distribution of air throughout the cabin of the aircraft, flow regulation, and/or other functions in managing airflow. The movement of air to different locations during the operation of the systems occurs through a duct system in the aircraft.
Further, the flow of air through the duct system also may be used to cool equipment in the aircraft. Without proper cooling, equipment may be overheated and may not function as desired. If the equipment receives more airflow than needed, other areas, such as the passenger cabin, may not be cooled as much as desired.
In controlling airflow through a duct system, airflow sensors and airflow controllers may be placed in different locations in the ducts within a duct system. The airflow sensors and airflow controllers may be used to manage the airflow within the duct system.
However, duct systems may have complex configurations such that the airflow is not consistent throughout the duct systems. For example, a duct system may have multiple bends, different diameters, splits, and other features that may affect the airflow.
These different features may result in different velocities of airflow in different locations of the duct system or different velocities of airflow across a cross-section of the duct system. With these different features, eddy currents may occur in the airflow in one or more different portions of the duct system.
If an airflow sensor is placed in a location where an eddy current occurs, the velocity of the airflow measured by the airflow sensor may not be as high as expected for the duct system based on the airflow into the duct system. As a result, an airflow sensor may not provide as accurate of an indication of the velocity of the airflow as desired, for example, across a cross-section of the duct, depending on the location of the airflow sensor within the duct system.
As a result, the different systems controlling the airflow controller may not provide a desired level of airflow for functions, such as cooling, heating, removal of undesired gases, and other functions within the aircraft. Thus, equipment may operate at a higher temperature than desired, a passenger cabin may be warmer than desired, a flight deck may be cooler than desired, and/or other undesired effects may occur. Therefore, it would be desirable to have a method and apparatus that takes into account at least some of the issues discussed above, as well as other possible issues.